DE 20 2012 103 410 U1 discloses an illumination device in which a number of light elements arranged in a row are arranged commonly on an elongated support arranged on a guide rail. This has the drawback that all undamaged light elements, together with the elongated support, must always be replaced when one of the light elements fails, which requires demanding installation work. Replacement of individual light elements, which are energy-saving or have other illumination functions, is also demanding even when the light elements are functioning.